LEDs are an efficient source of bright light for use in computer monitors, televisions, cellphones, and many other lighting applications including architectural, outdoor, commercial, and residential lighting. LEDs typically only emit light at one particular wavelength. For human eyes to perceive the color white, a mixture of wavelengths is needed. One conventional technique for emulating white light with LEDs includes depositing a conversion material (e.g., a phosphor) on an InGaN base material. In operation, the InGaN base material emits light in the visible blue spectrum that stimulates the conversion material to emit light in the yellow spectrum. The combination of the blue and yellow emissions appear white to human eyes if matched appropriately. If not matched appropriately, however, the combined emissions appear off white and reduce color fidelity of electronic devices. Accordingly, several improvements in color matching/correction may be desirable.
Conventional methods for constructing the LED and phosphor material include coating an LED with a slurry of phosphor and a carrier such as silicone. Other methods create a separate phosphor material, spaced apart from the LED, also made from a phosphor and silicone slurry. For example, U.S. Pat. No. 5,959,316 to Lowery discloses a semiconductor device with an LED and a transparent spacer that separates the LED from a uniformly thick fluorescent material. The conventional methods suffer from many difficulties. For example, phosphor particles tend to settle in a slurry, which changes the density and therefore the coverage uniformity of the phosphor material. Also, heat from the LED can reduce the efficiency of the phosphor material.